الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Work related asthma is the most common occupational lung disease with an incidence
of 2–5 cases per 100000 population per year, corresponding to about 15–20% of overall adult
onset asthma. Work-related asthma includes two major types of disease: occupational asthma
(OA), which is caused by respiratory sensitizer agents that found at work place and workexacerbated
asthma (WEA), which is asthma worsening by conditions at workplace. Work
related asthma is associated with adverse clinical and socioeconomic outcomes.
In wool mill factories, workers are exposed to several sensitizer agents (wool dusts,
animal protein, dying agents and agents from sheep enviroments) especially at sections with
dusty operations such as in carding, washing, dying and weaving sections which lead to
multiple respiratory health effects.
The diagnosis of work related asthma should be utilized in stepwise approach to reach
the proper diagnosis include: questionnaire, clinical findings, pulmonary function,
immunological and inflammatory tests and radiological assessment. The diagnosis of WRA
cases is not straightforward and can be a challengeable for clinicians. Every new adult-onset
asthma case should be considered a potential case of WRA and high level of suspicion is
essential to prevent adverse outcomes. The diagnosis recently focus on the role of cytokines
such as IL-5 and other cells such as eosinophil as key cells in asthma. The IL-5 is the most
specific cytokine in the eosinophil lineage, and has been identified as the key denominator in
inflammatory pathways in asthma. It plays a role in eosinophil proliferation, differentiation,
maturation, migration to tissue sites and survival, as well as prevention of eosinophil
apoptosis
High-resolution computed tomography (HRCT) has emerged as a repeatable and
accurate tool as a non-invasive method to assess proximal airway and lung parenchyma to
reveal abnormal radiologic findings, such as bronchial wall thickening, bronchial wall
dilatation, mosaic lung attenuation, mucus plugging, prominent centri-lobular opacities,
emphysema, atelectasis and air trapping.
The primary objective of this study was to determinate the role of HRCT of the lung and
some serum biomarkers in diagnosis of work related asthma among workers exposed to wool
dusts. The study was carried on 120 asthmatic workers divided into two equal groups, exposed
workers (group I) and non-exposed workers (group II). Both groups were matching regarding age,
gender, smoking history and duration of work. The workers participated in our study were
selected from STEA wool factory at Alexandria governorate.
All workers in the study were subjected to complete history taking, full general and
chest examination, physiological test (PFTs), laboratory investigations (CRP, eosinophil, IgE
and IL-5) and radiological examination by HRCT.
The results of pulmonary function in group I was significantly lower than that of group
II (69.7± 9.6) vs. (78.15± 12.07) for FEV1, (95.4± 11.39) vs. (102.4± 11.64) for FVC, (72.96±
11.3) vs. (75.775± 11.34) for FEV1/FVC.For evaluation of airway inflammation, serum biomarkers were another remarkable tool
in asthma diagnosis and prognosis. At group I the level of serum biomarkers was also
significantly higher than group II. For the degree of sensitivity and specificity of the
biomarkers, the serum IgE was the most sensitive biomarker for diagnosis of work related
asthma with 73.3%, and AUC 0.718*. And IL-5 was the most specific biomarker with 90%
specificity for diagnosis of work related asthma among wool exposed workers.
As regard radiological imaging, HRCT of the lung enable us to view airway structural
changes and parenchymal abnormality. Bronchial wall thickness of proximal airways,
bronchial dilation, mucous impaction, mosaic pattern appearance, air trapping, atalectatic
bands and centrilobular emphysema were the most important pathological radiological
changes among asthmatic subjects. Generally the endpoint HRCT changes were higher in
group I than in group II 88.3% vs. 76.6%. As regard sensitivity and specificity bronchial wall
thickness was the parameter with highest sensitivity and the air trapping was the most specific
parameters in diagnosis of asthma at exposed workers.
According to the result of our study, it was proved continuous exposure to sensitizer
agents at work place is the main cause of exaggerate clinical, physiological, pathological and
inflammatory changes in exposed workers when compared to non-exposed workers. The
serum biomarkers and HRCT of the lung have promising role in early diagnosis of asthma to
decreases the rate of late effect of asthma as regard heath, economic and social disabilities.
Summary, Conclusions & Recommendation
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6.2 Conclusions and Recommendation:
1. Exposure to wool dusts at dusty work place leading to multiple respiratory complains
and morbidity including work related asthma either in form of occupational asthma or
work exacerbating asthma.
2. Diagnosis of work related asthma should be by objective method. Pulmonary function tests
are the most important tool for diagnosis of air way obstruction and reversibility.
3. HRCT of the lung is an accurate tool to visualize airway structure and lung
parenchyma. It is considered as non-invasive alternative tool instead of invasive
pathology in diagnosis of asthma.
4. Bronchial wall thickness is the most sensitive parameter in asthma diagnosis by HRCT.
5. Serum biomarkers for asthma are important tool in studying the inflammatory
mechanism of asthma, phenotypes and severity.
6. Serum IgE is the most sensitive biomarkers in asthmatic workers due to exposure to
wool dusts.
7. Serum IL-5 is the most specific biomarker in diagnosis of asthma severity.
8. We recommend to use HRCT of the lung and serum biomarkers (eosinophil, IgE &IL-
5) as a promising tools for early detection of work-related asthma.
9. We recommend to do further study about the role of biomarkers and HRCT of the lung
for early detection of work-related asthma.